The Adept Quattro s650H is an industrial robot with four parallel arms mounted
on a rotational body. The arms are extensions of four motors, one motor per
appendage. These arms are a good fit for processing crystalline silicon wafers for
solar cells as they produce more solar cells per hour than human employees do.

Silicon Wafer Processing

The Adept Quattro s650H robots transfer the wafers
through a variety of processes. These include loading the
wafers on to a conveyor belt system so that they can be
transported to and through the PECVD process. The PECVD
process uses a plasma-enhanced chemical vapor deposition
— also referred to as anti-reflective coating — in which the
wafers are doped with phosphorus, screen printed, and
sorted according to their final quality or classification,
according to Kevin Stein, Applications Engineer, Adept

One of Adept’s industrial robots —
the Viper 650 table mounted arm.

10 SERVO 10.2009

Technology, Inc. “Individual wafers get transferred in and
out of these process machines by Quattro,” explains Stein.

The robots handle the wafers individually with great
care and precision. In the past, human operators handled
the wafers. “But robots provide higher efficiency and less
waste by decreasing the breakage rate. The Adept Quattro
robot provides less than 0.1% breakage depending on the
application and type of cell handled. Robots do not get
tired, take breaks, or call in sick,” says Stein. The efficiency
of the Quattro reduces the cost per watt of solar
production, Stein adds, giving the manufacturer a
competitive advantage.

“The cost per watt is the amount of money spent to
deliver usable energy. The most frequent use of the
terminology is by energy companies who say it costs “x”
dollars per kilowatt hour of electricity. Using Quattro
to increase solar cell production efficiencies through
automation ultimately costs that manufacturer less
money to produce the same amount of energy. Therefore,
reducing the cost per watt,” Stein explains.

Quattro Mechanics

According to the Quattro User Guide, “the Adept
Quattro s650H robot is a four-axis parallel robot … four
identical axis motors control movement of the robot tool
in X, Y, and Z directions, as well as Theta rotation.” As
previously mentioned, four robotic arm linkages are
attached to the robot’s rotational platform. This is unique
as compared with traditional three-arm robots. “It earns the
Adept Quattro the unique title as the first of a new class of
robots called Delta- 4 Kinematic,” Stein explains.

According to Stein, this is all part of what is referred to
as the robot’s kinematics. The kinematics are derived from
the underlying algorithms that coordinate rotational motion
(from the motors) to translation/linear motion (tooling